I am looking at buying a used 1999 328is with 93,500 miles. The 328 has an M3 body style and has been upgraded with a Dinan performance chip. The asking price is $13,800, but the owner will trade it in at a BMW dealer if he doesn't sell it in a few weeks. The body is in good condition. Is it a good deal? Is it unusual to have an M3 body style? Any advice would be appreciated.